Influence of hormonal extracts on hens producing eggs with non-calcified or partially calcified shells and factors associated with this condition.

1. Daily injection of hypothalameal extract (HE) and adenohypophyseal extract (AE) into hens aged 56 or 67 weeks for 14 d did not significantly influence the production of shell-less (SL) or ultra-thin-shell (UTS) eggs. 2. The injection of HE significantly increased hard-shell (HS) egg production in the younger hens. 3. Neither AE nor HE affected egg weight, serum calcium, gain in body weight or food consumption. 4. In a third experiment hens selected for poor egg production laid at a rate of 58% of which 36% were SL, 29% UTS and 35% HS eggs. Whereas the production rate of the good layers was 65% of which 1-4% were SL and 1-4% were UTS eggs. 5. Specific gravity of HS eggs, serum calcium, weight of ovary, oviduct, or adenohypophysis did not differ between good and poor layers. 6. Since SL and UTS eggs are easily overlooked the decrease in egg production with age may be as great as indicated by normal production records; the problem may be concerned more with the mechanism of shell formation.     

Assessment of attenuated Salmonella vaccine strains in controlling experimental Salmonella Typhimurium infection in chickens

Salmonella hold considerable promise as vaccine delivery vectors for heterologous antigens in chickens. Such vaccines have the potential additional benefit of also controlling Salmonella infection in immunized birds. As a way of selecting attenuated strains with optimal immunogenic potential as antigen delivery vectors, this study screened 20 novel Salmonella Typhimurium vaccine strains, differing in mutations associated with delayed antigen synthesis and delayed attenuation, for their efficacy in controlling colonization by virulent Salmonella Typhimurium, as well as for their persistence in the intestine and the spleen. Marked differences were observed between strains in these characteristics, which provide the basis for selection for further study as vaccine vectors.     

A presumably exotic Phytophthora species causing dieback of Buxus sempervirens in Germany and Romania

Journal of Plant Diseases and Protection - Roots, collars and rhizosphere soils from diseased boxwood saplings (Buxus sempervirens) from German and Romanian nurseries were shown to be colonized by...     

Pesticide exposure assessment for surface waters in the EU. Part 1: Some comments on the current procedure

In 2001, the European Commission introduced a risk assessment project known as FOCUS (FOrum for the Coordination of pesticide fate models and their USe) for the surface water risk assessment of active substances in the European Union. Even for the national authorisation of plant protection products (PPPs), the vast majority of EU member states still refer to the four runoff and six drainage scenarios selected by the FOCUS Surface Water Workgroup. However, our study, as well as the European Food Safety Authority (EFSA), has stated the need for various improvements. Current developments in pesticide exposure assessment mainly relate to two processes. Firstly, predicted environmental concentrations (PECs) of pesticides are calculated by introducing model input variables such as weather conditions, soil properties and substance fate parameters that have a probabilistic nature. Secondly, spatially distributed PECs for soil–climate scenarios are derived on the basis of an analysis of geodata. Such approaches facilitate the calculation of a spatiotemporal cumulative distribution function (CDF) of PECs for a given area of interest and are subsequently used to determine an exposure concentration endpoint as a given percentile of the CDF. For national PPP authorisation, we propose that, in the future, exposure endpoints should be determined from the overall known statistical PEC population for an area of interest, and derived for soil and climate conditions specific to the particular member state. © 2016 Society of Chemical Industry     

Sprouting Ability and Seasonal Changes of Sugar Concentrations in Rhizomes of Calystegia sepium and Roots of Convolvulus arvensis

Journal of Plant Diseases and Protection - Factors influencing the sprouting ability of rhizome pieces of Calystegia sepium and root pieces of Convolvulus arvensis were analyzed in four...     

Winter wheat yield loss in response to Avena fatua competition and effect of reduced herbicide dose rates on seed production of this species

Journal of Plant Diseases and Protection - Avena fatua is one of the most abundant and competitive grass weed species in cereal cropping systems worldwide. Despite its main occurrence in summer...     

Multi-scale Modeling of Animal Movement and General Behavior Data Using Hidden Markov Models with Hierarchical Structures

Hidden Markov models (HMMs) are commonly used to model animal movement data and infer aspects of animal behavior. An HMM assumes that each data point from a time series of observations stems from one of N possible states. The states are loosely connected to behavioral modes that manifest themselves at the temporal resolution at which observations are made. Due to advances in tag technology and tracking with digital video recordings, data can be collected at increasingly fine temporal resolutions. Yet, inferences at time scales cruder than those at which data are collected and, which correspond to larger-scale behavioral processes, are not yet answered via HMMs. We include additional hierarchical structures to the basic HMM framework, incorporating multiple Markov chains at various time scales. The hierarchically structured HMMs allow for behavioral inferences at multiple time scales and can also serve as a means to avoid coarsening data. Our proposed framework is one of the first that models animal behavior simultaneously at multiple time scales, opening new possibilities in the area of animal movement and behavior modeling. We illustrate the application of hierarchically structured HMMs in two real-data examples: (i) vertical movements of harbor porpoises observed in the field, and (ii) garter snake movement data collected as part of an experimental design. Supplementary materials accompanying this paper appear online.     

Schnelle und einfache Methode zum Nachweis der Fenhexamid-Resistenz bei Botrytis

Isolates of Botrytis cinerea collected from Northern German strawberry and raspberry farms were grouped into three categories according to their pattern of resistance against the fungicide fenhexamid. Strains with baseline sensitivity showed EC₅₀ values of 0.06–0.10 ppm (conidial germ-tube elongation) and 0.07–0.16 ppm (mycelial growth assay). For partially resistant isolates, the corresponding EC₅₀ values were similar for germ-tube elongation but higher (> 0.39 ppm) for mycelial growth. Highly resistant isolates produced more than 50% growth in both assays even at 200 ppm fenhexamid, the highest concentration tested. These isolates matched the criteria of resistance group Hyd R3. By means of a simple test consisting of the harvesting of conidia from sporulating field samples and their direct assay by germ-tube elongation, Hyd R3 resistance was identified within 24 h of sampling. If this assay is performed on overwintered samples prior to blossom time, site-specific recommendations about the use of fenhexamid can be made to the farmer during the running vegetation period.